I. The present invention relates to a backpack.
II. There are many previously known backpacks which have a front, top, bottom, side and back panels which as an assembly define the chamber within for carrying objects. A pair of shoulder straps are secured to the backpack so that when the backpack is worn, the backpack is supported on the back of the person. Such backpacks are of the type used by students for carrying academic supplies.
Sadler describes a backpack as described above and which has a pad assembly having a first and second generally planar pads, each having a top, bottom and two sides. The bottoms of the pads are pivotally secured together between a first position in which the first pad overlies and is substantially parallel to the second pad, and a second position in which the plane of the first pad is substantially perpendicular to the plane of the second pad. The top and sides of the first pad are secured to the top and sides of the second panel so that, with a back of a chair positioned in between the first pad and first panel, the chair supports the pack behind the back of the chair. Sadler describes how this design can be used to conveniently store the backpack in a classroom.
For the Sadler configuration, the pivotal pad assembly as positioned for transportation places the second pad which pivots onto the seat of the chair behind the first pad. In the transportation mode, the lumbar relief of the first pad interfaces with the second pad as pivoted behind it on the backpack. Because of the design, this position does not give the same lumbar relief benefits which is attained when the backpack is positioned over the back rest of the chair.
Secondly, the Sadler invention requires a design consisting of two cushioning pads which constitutes a dual padding assembly adding width to the backpack during transit. The additional bulk is attributed to the second pad pivoted behind the first pad.
Thirdly, the strapping mechanism which combines the pad assembly to the backpack requires sufficient clearance so that the second pad can pivot and fold behind the first pad. This clearance distance may not be ideal for the variations of desk seats and chairs within an academic environment. Therefore, alterations may be required to reposition the backpack from its transportation mode to its position on the back rest of the chair.
Finally, the preferred embodiment of the Sadler invention includes 2 straps; one at the top and one on each side. Each strap has a buckle mechanism which provides the ability for the pivotal pad assembly to be removed from the back side of the backpack. The mechanism for interfacing the pad assembly to the backpack and the dual pivotal pad assembly incur significant costs. The buckle mechanism also creates a potential of snag point of the pad assembly on the back rest of the chair when positioning the backpack in place.